A method for indirectly monitoring and controlling an electrically resistive adsorption system. Adsorption of a predetermined adsorbate is conducted while...
A method for indirectly monitoring and controlling an electrically resistive adsorption system. Adsorption of a predetermined adsorbate is conducted while indirectly monitoring electrical resistance of a unified adsorbent element. Breakthrough is predicted based upon the indirectly monitored electrical resistance and a previously measured mass loading relationship between the resistance of the unified adsorbent element and the loading of the unified resistance element with the predetermined adsorbate. Adsorption, regeneration and cooling cycles are controlled by a controller without any direct measurement of temperature or resistance of the element and characterizations of mass loading and temperature. Systems of the invention can have no sensors that contact the element, are in an adsorption vessel, and/or are downstream adsorption vessel.
Many manufacturing processes currently emit large quantities of gas effluent into the atmosphere or dispose of by techniques such as thermal oxidation or bio-...
Many manufacturing processes currently emit large quantities of gas effluent into the atmosphere or dispose of by techniques such as thermal oxidation or bio-filtration (which both consume auxiliary fuel and produce CO2). These are usually carrier gases that contain dilute concentrations of organic gas (contaminants). This invention is a new device process for separating dilute gas(es) (e.g. organic gases) from gas streams for reuse as a liquid or other useful purposes (e.g. auxiliary fuel or chemical manufacturing).
The invention provides gas purification methods and systems for the recovery and liquefaction of low boiling point organic and inorganic gases, such as methane, propane, CO.sub.2, NH.sub.3, and chlorofluorocarbons. Many such gases are in the effluent gas of industrial processes and the invention can increase the sustainability and economics of such industrial processes. In a preferred method of the invention, low boiling point gases are adsorbed with a heated activated carbon fiber material maintained at an adsorption temperature during an adsorption cycle. During a low boiling point desorption cycle the activated carbon fiber is heated to a desorption temperature to create a desorption gas stream with concentrated low boiling point gases. The desorption gas stream is actively compressed and/or cooled to condense and liquefy the low boiling point gases, which can then be collected, stored, re-used, sold, etc. Systems of the invention include an active condensation loop that actively cools and/or compresses a desorption gas stream from said vessel to liquefy low boiling point gases.
The University's Vapor Phase Removal and Recovery System (VaPRRS) is a patented long-lasting filter that effectively removes dilute volatile organic compounds (...
The University's Vapor Phase Removal and Recovery System (VaPRRS) is a patented long-lasting filter that effectively removes dilute volatile organic compounds (VOCs) and hazardous air pollutants (HAPs) from gas streams and recovers them as pure liquids. The technology can be integrated into a variety of manufacturing facilities and air pollution control (APC) systems to make them more effective. VaPRRS is a VOC/HAP recovery system that uses an activated carbon fiber cloth and electrothermal desorption (ED) to inexpensively and selectively remove vapors from gas streams. The system rapidly adsorbs and then efficiently regenerates the sorbent and allows for condensation of the sorbate gas all within one control volume. Experimental and numerical prototyping has successfully demonstrated the removal of 4-methyl-2-pentanone (MIBK), toluene, methyl propyl ketone (MPK), methyl ethyl ketone (MEK), and hexane from laboratory generated air steams.
This technology uses activated-carbon fiber cloth (ACFC) as an alternative adsorbent to traditional granular activated carbon (GAC) to remove and recover organic vapors from gas streams. The ACFC is microporous, has up to 250% of the adsorption capacity of GAC, has faster mass and heat transfer properties than GAC, and is ash free to inhibit chemical reactions between the ACFC and the adsorbed vapors. Electrothermal desorption can be used to rapidly regenerate the ACFC with lower energy requirements than steam- or heated nitrogen-based regeneration. ED also eliminates the need for an adsorbent drying step and the recovered solvent/water separation processes usually required with conventional steam regeneration technology.
As shown in Figure 1 attached, this technology consists of two adsorption/desorption units that enclose hollow elements containing ACFC and provide gas ports at either end. The compounds are adsorbed onto ACFC cartridges (Figure 2 attached) that are electrothermally regenerated at a very rapid rate, causing the adsorbate to condense within the adsorption vessel itself and produce two-phase flow of the effluent during regeneration. The ACFC elements provide controlled electrical resistance, allowing for direct electrothermal heating and rapid regeneration of the ACFC and recovery of the VOCs/HAPs. Rapid ED with in-vessel condensation results in significant reductions in system complexity, cycle times, and nitrogen consumption. This new system also operates without the use of steam, heated inert gas, vacuum, or a refrigeration system. The pilot-scale system regenerates the ACFC within 40 minutes.
Continuous VOC/HAP capture and recovery tests were performed with the bench-scale unit (125 mm diameter) while removing an array of solvents at a total gas flow rate ranging from 5-85 sLpm. The adsorption vessel contained 128 grams of ACFC. Single-component organic vapor tests were performed with MIBK; toluene; n-hexane, 2-pentanone (MPK); MEK; and n-hexane with controlled concentrations ranging from 100 to 10,000 ppmv in air. Overall removal efficiencies of greater than 99% were measured during the experiments.
Companies can license the VaPRRS technology for integration into existing manufacturing operations and APC systems for a wide variety of applications, including:
Manufacturing: This technology can be used to recover VOCs/HAPs generated during the manufacturing of various products, including:
This technology is a microcombustor a compact, submillimeter device that burns hydrocarbon fuels homogeneously as a source of power. It efficiently converts heat...
This technology is a microcombustor a compact, submillimeter device that burns hydrocarbon fuels homogeneously as a source of power. It efficiently converts heat generated by combustion into electric power, and has the potential to replace batteries in portable applications requiring long-term power. This device is actually the burner, and will eventually form the core of a system that includes peripheral technologies, such as thermal isolation.
This microcombuster is designed to burn hydrocarbon fuels homogeneously and to convert generated heat into electric power, on a compact, submillimeter scale. While this technology provides the burner, it will ultimately be developed as the central element in a suite of peripheral technologies, such as thermal isolation, enabling it to be functional on a practical scale (i.e., be worn by military personnel).
This technology burns hydrocarbons in homogeneous combustion. It has attained temperatures over 1,000 C. The higher the temperature, the more efficient the conversion to electric power will be (the higher the practical power density). The development of the microcombustor addresses two essential technological problems: the need for a wall material that retards/prevents radical formation; and, a wall material that can withstand very high temperatures. Various materials are being tested for the microcombustor and the underlying physics of the device are being determined. The wall material of this device required a chemistry that does not force recombination of radicals at the wall, as by catalysis (a process that would quench the flame).
This technology uses a combination of silica, alumina, and magnesium to create a wall that disallows recombination and also rejects the radicals, returning them to the gas phase to continue to react. These materials also can tolerate high temperatures, an important factor in solving the second problem. The walls of the microcombustor must be able to tolerate very high temperatures-more than 1,000 C-to preserve efficiency.
As an alternative to thick walls, which would make the device rather large, a thermal isolation technology is under development that will enable thin walls to be hot on the inside while their outsides remain cool. This will allow the microcombustor to be worn in close proximity to a user.
The microcombustor gives a very high practical power density. Batteries that produce high energy density are often too heavy and, typically, have low power density (and vice versa). They cannot provide the energy density required for many high-power applications, for light weight, for any extended period. Compared to the highest possible energy density battery, which may someday provide 2,000 kwh/kg, homogeneous combustion yields up to 18,000 kwh/kg, a nine-fold enhancement.
The microcombustor, due to its very small size and weight, can deliver extremely high power density for extended periods of time, which cannot be matched by batteries of any type. If used as a heat source for microchemical reactors, the system would involve sandwiching the microcombustor between microreactors and then insulating the package. This type of microreactor can then be used to generate a wide range of chemicals, on the spot, for various applications in industry.
This is particularly true for chemicals that are difficult to make and store, or are expensive, unstable, or toxic, thus requiring only very small quantities. For power generation, the reactor can be used to generate hydrogen gas for fuel cells, on demand, without requiring hydrogen to be stored, thereby increasing safety. By itself, if the microcombustor was used in a thermophotovoltaic system, it would be the alternative to solar cells and thermoelectricity, which are inefficient and not popular.
The microcombuster is designed for applications where a lot of power is needed quickly, in a small package.